Optical waveguide crosstalk SPICE modeling for package system signal integrity simulation

A SPICE modeling method for optical waveguide crosstalk in intensity modulated optical link is proposed based on the data from hardware sample measurements or electromagnetic simulations at optical wave frequencies. The proposed equivalent baseband SPICE model is for the applications of signal integrity transient simulation by using general-purpose SPICE or SPICE-like circuit simulators with marching time steps in the electrical signal envelop regime. In addition to crosstalk modeling, the proposed method can also be applied to transmission modeling directly. The amplitude of the optical transmission/crosstalk in optical wave frequency-domain is applied directly to the equivalent baseband SPICE model. The group delay of the optical wave transmission/crosstalk is taken as the phase delay of the transmission/crosstalk in the equivalent baseband SPICE model. The phase of the optical wave carrier is handled by DC nodes and nets in the SPICE model for superposition of crosstalk and victim signal. To estimate the worst case scenario of the crosstalk effect on the electrical signal eye diagram caused by the optical carrier phase difference between crosstalk aggressor and victim, two or more transient simulations are applied to combine different optical wave phase offsets between crosstalk aggressor and victim. Signal integrity test cases on optical waveguide SPICE models combined with the VCSEL optical transmitter or Mach-Zehnder intensity modulator and optical receiver SPICE models are shown to test the proposed modeling and transient simulation method. Test examples include polymer multimode optical waveguide on card/board level and some single mode optical waveguide structures at in-package and on-chip levels such as Silicon, SiO₂, and plasmonic optical waveguides.